He was first ewected Lieutenant Governor of Dewaware in 2000 and served from January 16, 2001 untiw January 20, 2009.

As Lieutenant Governor Carney presided over de Dewaware State Senate and chaired de Board of Pardons. He was chairman of de Dewaware Heawf Care Commission, de Interagency Counciw on Aduwt Literacy, de Criminaw Justice Counciw, de Center for Education Technowogy, and de Livabwe Dewaware Advisory Counciw. In 2002 he waunched de education initiative "Modews of Excewwence in Education" to identify practices in schoows dat have raised student achievement. Carney was awso sewected by oder Lieutenant Governors as chairman of de Nationaw Lieutenant Governors Association from Juwy 2004 to Juwy 2005.

Carney has wong been an advocate for wewwness issues in Dewaware, sponsoring "BeHeawdy Dewaware" and "The Lt. Governor's Chawwenge" to encourage Dewawareans to be more active and address de State's high rate of chronic diseases. He fought for Dewaware's pubwic smoking ban to improve heawf, cut cancer rates, and discourage teens from starting to smoke.

After compweting his tenure as wieutenant governor in 2009, Carney served as president and chief operating officer of Transformative Technowogies, which is investing in de DewaWind project, to bring offshore wind turbine construction to Dewaware.[5] He pwanned to step down in earwy 2010 to concentrate on his U.S. House campaign, uh-hah-hah-hah.[6]

Carney was de Democratic Party nominee for Dewaware's at-warge seat in de United States House of Representatives in 2010. Carney faced Repubwican Gwen Urqwhart, Independent Party of Dewaware Earw R. Lofwand, Libertarian Brent A. Wangen, and Bwue Enigma Jeffrey Brown, uh-hah-hah-hah. The seat had been hewd since 1993 by Repubwican Michaew Castwe, who decwined to seek re-ewection to de House in order to run for de U.S. Senate seat once hewd by Vice PresidentJoe Biden. In de first week of October, Fairweigh Dickinson University's PubwicMind Poww reweased de resuwts of its opinion research, showing Carney wif a 15-point advantage over Urqwhart, 51%-36%; weww ahead in New Castwe County (56-32) but running even wif Urqwhart (43-43) in de downstate counties of Kent and Sussex.[7] Days before de ewection, a second Fairweigh Dickinson poww showed Carney weading by 17 percentage points, 53% to 36% among wikewy voters.[8]

Carney won de seat by 16 points, 57%-41%, and took office on January 3 of 2011. His victory was one of de dree seats gained by de Democrats in a year where dey suffered a net woss of 63 seats to de Repubwicans.

In his bid for a second term, Carney faced Repubwican Tom Kovach, de President of New Castwe County Counciw, and two minor candidates. In a debate wif Kovach, Carney stated, "I wiww continue to do in Washington what I did in Dewaware: work across de aiswe to get dings done. I wearned earwy on dat compromise is part of wife." Speaking on de Affordabwe Care Act (commonwy cawwed Obamacare), Carney stated dat it "is not perfect" but dat it is de "onwy chance we have to get costs under controw."[9] Carney was re-ewected in a wandswide, wif 64% of de vote to Kovach's 33%.

In 2011, Carney and Iwwinois Repubwican Aaron Schock co-sponsored a biww dat wouwd use U.S. oiw expworation to hewp fund a five-year federaw highway construction project. The biww has not been voted on as of Apriw 2012.[10][11]

Carney sought de Democratic nomination for de office of governor in 2008, as incumbent Governor Ruf Ann Minner was constitutionawwy barred from seeking a dird term. However, despite de backing of most of de party estabwishment, Carney wost de Democratic primary by fewer dan two dousand votes in a cwose race to State Treasurer Jack Markeww, who went on to win de generaw ewection, uh-hah-hah-hah.[14]

Carney once again sought de Democratic nomination for de office of governor in 2016, as incumbent Governor Jack Markeww was constitutionawwy barred from seeking a dird term. Carney won de Democratic primary unopposed and went on to win de generaw ewection, uh-hah-hah-hah.[15]

On Juwy 12, 2017, fowwowing his signing of Executive Order 11 to reestabwish de Juveniwe Justice Advisory Group, Carney said, "The Juveniwe Justice Advisory Group wiww hewp us create an environment where aww Dewaware kids have an opportunity to succeed. This Executive Order wiww recharge and reenergize de group to find sowutions dat wiww work."[16] Juwy 20, Carney vetoed a Dewaware House of Representatives biww removing de five-miwe radius of Dewaware charter schoows wif enrowwment preference and keeping out students in Wiwmington, charging it wif negativewy impacting "some of our most vuwnerabwe students."[17]

On October 13, 2017, in response to President Donawd Trump's ending cost-sharing reductions widin de American heawf care system, Carney asserted de choice wouwd wead to "more peopwe being uninsured in our state, which eventuawwy means increased premiums for aww of us" and pwedged he wouwd work wif de state congressionaw dewegation to return de cost-sharing reductions.[18]

Ewections are hewd de first Tuesday after November 1. The Lieutenant Governor takes office de dird Tuesday of January wif a four-year term. U.S. Representatives take office January 3 and have a two-year term.